Date Rewarded: May 30rd, 2001.

Siya the Usuki Doll (pictured above) is 9 years older than her brother, and 25 years younger than her father. In seven years time her father will be three times older than her brother. How old is Siya now?

Prize

Unknown

Unknown

__Click to show/hide solution__

Let x be Siya's age, y be her brother's age and z be her father's age. We know:

y = x - 9

z = x + 25

z = x + 25

In seven years, her brother's age and her father's age will be x - 2 and x + 32 respectively (add 7 to y and z). Her father's age will be three times her brother's age then. Therefore,

x + 32 = 3 * (x - 2) <=> x + 32 = 3x - 6 <=> 2x = 38 <=> x = 19

Therefore, Siya is 19 years old now.

__Check__: her brother's age = 10, her father's age = 44. In seven years, her father's age = 51, three times as much as her brother's age = 17.

__Note__: The picture is missing.

## No comments:

Post a Comment